POWER MANAGEMENT

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SC2621A

Voltage Mode PWM Controller With

Linear Power Regulator

Features

Applications

February 21, 2007

Typical Application Circuit

Description

The SC2621A provides the control and protection fea-

tures necessary for a synchronous buck converter and a

linear regulator in high performance graphic card appli-

cations.

The SC2621A is designed to directly drive the top and

bottom MOSFETs of the buck converter. It uses an inter-

nal 8.2V supply as the gate drive voltage for minimum

driver power loss and MOSFET switching loss. It allows

the converter to operate with 4V to 25V power rail and

as low as 0.5V output. The SC2621A is capable to drive

a N-type MOSFET in a linear regulator with as low as 0.5V

output.

The SC2621A features soft-start, supply power under

voltage lockout, and hiccup mode over current protec-

tion. The SC2621A monitors the output current by using

the Rdson of the bottom MOSFET in the buck converter

that eliminates the need for a current sensing resistor.

The SC2621A is offered in SOIC-14 package.

shoot-through protection for MOSFETs

platform

12V IN

1.5V OUT

U2

S C2 621A

1

2

3

4

10

11

12

14

5

13

6

7

9

8

BST

OCS

COMP

FB

DRV

DL

GND

DH

LDOG

PN

LDFB

GND

NC

VCC

+

+

2.5V OUT

3.3V IN

+

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